Finding acceptable coatings for foods, such as fresh fruits, vegetables, cheeses, bakery goods, raw and cooked eggs, fresh and processed meat and seafood products is a challenging task. The desired coating would be edible and once applied would act as a barrier to moisture, gases and/or UV light, and undesirable microorganisms. However, several other criteria must also be met. The coating must be completely harmless to consumers, transparent, or nearly so, in the visible region so the product is visible to the consumer, and impart no significant odor or taste to the foods. In addition, edible coatings that offer promise as packaging materials due to one or more unique functional properties often suffer from reduced water resistance (highly water soluble). Satisfying all these criteria simultaneously and satisfactorily has presented a serious challenge to researchers and as yet no suitable solution has been found.
Anthocyanins provide the majority of red, purple, and blue pigmentation of fruits, and their greater consumption has been suggested to mitigate the risk of chronic disease in humans. Unfortunately, these pigments are highly labile and vulnerable to degradation during thermal processing. Further complicating matters is their water-solubility that promotes their leaching into aqueous media. Thus, innovative technologies are needed to overcome long-standing technical barriers experienced by the food industry to retain these health-promoting pigments during crop production, harvesting, handling and processing.
Fresh produce (fruits and vegetables) and plants in general commonly lose water to their surroundings during production, harvesting, handling and storage. This water loss can cause damage, dieback, and death to plants in general, as well as changes in the appearance, texture and quality of the produce, which most consumers find unappealing. This results in a decreased marketability, and limits acceptable shelf-life and storage times.
Exposure to high levels of UV light can damage developing and maturing produce creating visibly damaged and discolored tissues, destroying native healthful phytochemical compounds, stimulating production of undesirable and harmful compounds like ethylene gas, and providing a foothold for spoilage organisms to grow. Such produce suffers a loss of perceived quality, reduced health benefits and generally deemed unsuitable for the fresh market. Further, the phenomenon can potentially ruin a grower economically, as the conditions leading to its occurrence are shared by the entire crop.
Previously frozen foods typically exude liquid during thawing, resulting in a phenomenon called “drip loss.” This can be off-putting to consumers, and can change the overall composition of the thawed product, making it behave differently from fresh during preparation/cooking. Drip loss also can cause economic losses to the processors.